Efficacy of ethacrynic acid in patients with refractory congestive heart failure resistant to meralluride

The management of acute heart failure and diuretic therapy

One million patients are hospitalized each year with acute decompensated heart failure, and up to 20% of these patients are rehospitalized within a month after the acute presentation. Acute heart failure (AHF) accounts for 50,000 deaths annually and is the most frequent reason for hospital admissions in the United States. This article reviews the therapeutic options and the results of recent clinical trials in the treatment of AHF. Most patients can be effectively managed by use of diuretic agents or diuretics in combinations with nitrates, IV nitroglycerin, IV nitroprusside, and possibly IV nesiritide. Ultrafiltration is a promising technique that can be very helpful in the resistant patient. However, given the ease of initiation of diuretic therapy, it is unlikely that ultrafiltration would supplant diuretic use in acutely symptomatic patients. Patients in acute distress with AHF almost invariably respond to diuretics or a vasodilator combined with diuretic therapy. The loop diuretics are the most effective diuretics and thus most frequently used agents in treating AHF. Currently, there are 4 loop diuretics in the US market: furosemide, bumetanide, torsemide, and ethacrynic acid. IV furosemide and ethacrynic acid have a prompt venous dilatory effect, consequently decrease left ventricular filling pressure and immediately relieve symptoms of pulmonary congestion, before a diuresis can occur. Furosemide is more often used than ethacrynic acid due to its reduced ototoxic potential. However, ethacrynic acid should be used in sulfa-sensitive patients because ethacrynic acid is the only loop diuretic, which does not contain a sulfa moiety.

The clinical pharmacology of ethacrynic acid

Ethacrynic acid (Edecrin) is a loop diuretic that produces a prompt and profound diuresis. The primary action of ethacrynic acid is the inhibition of the activity of the Na⁺-K⁺-2Cl⁻ symporter in the thick ascending limb of the loop of Henle. The onset of action is usually within 30 minutes after an oral dose and within 5 minutes after an intravenous injection. After oral administration, peak diuretic effect occurs in about 2 hours and the effect lasts about 6-8 hours. After intravenous administration, peak diuretic effect occurs within 30 minutes and the diuretic effect is virtually completed in 2-4 hours. The bioavailability of ethacrynic acid approximates 100%, with maximal blood level between 40 and 92 minutes. The elimination half-life has been reported to be less than 1 hour, but highly variable (average 30 minutes with a range of 12-160 minutes). Intravenous ethacrynic acid has a prompt venous dilatory effect and immediately relieves symptoms of pulmonary congestion, before a diuresis can occur. Ethacrynic acid is effective in all types of edema whether there is clinical acidosis, alkalosis, or electrolyte imbalance. Most side effects of ethacrynic acid can be attributed to its effectiveness (volume depletion); however, it may cause metabolic alkalosis that is preventable by KCl replacement. Ethacrynic acid has ototoxic effect that occasionally results in temporally or permanent deafness. Despite limitations, ethacrynic acid has been employed in the treatment of congestive heart failure and other edematous states, especially in patients allergic to sulfa-containing drugs because all the other loop diuretics have a sulfa moiety.

Ethacrynic Acid Can Be Effective for Refractory Congestive Heart Failure and Ascites

Ethacrynic acid is a loop diuretic little used today because of its side-effect profile and the availability of multiple alternative agents. However, in our clinical experience, ethacrynic acid can alleviate acute congestive heart failure and ascites resistant to other diuretics. Two patients aged 89 and 94 in life-threatening pulmonary edema were stabilized by ethacrynic acid after furosemide proved ineffective. A third patient, aged 83, with a pleural effusion and ascites secondary to end-stage hepatitis B and C, responded to ethacrynic acid when spironolactone and furosemide produced little urine output. Ethacrynic acid may have a unique niche as a diuretic of last resort, especially in geriatric practice.